Extractive Spectrophotometric Determination of Antiallergic Drugs in Pharmaceutical Formulations Using Bromopyrogallol Red and Bromothymol Blue

Abstract

In view of the extensive applications of compounds viz., methdilazine hydrochloride (MDH), promethazine hydrochloride (PMH), and isothipendyl hydrochloride (IPH) as antiallergic drugs, it is necessary to develop new analytical methods for their determination in bulk samples and pharmaceutical preparations. A variety of spectrophotometric methods based on colored complex formation or oxidative reactions have been proposed. Some are lacking sensitivity, 1-6 require heating 7,8 or long standing 9 for color development. The reported methods 1-5 suffer from twin disadvantages of critical acid or oxidant concentration and instability of the colored species, the stability ranging from 10 -40 min. The literature on the extractive spectrophotometric methods for the assay of the above drugs is scanty, although these methods are wellsuited. The official methods [10][11][12] (MDH, 12 PMH, 10 and IPH 11 ) involve non-aqueous titrations or UV spectrophotometric methods, which are tedious and time consuming.In the present paper, we report two extractive spectrophotometric methods based on the formation of ionassociation complexes between the antiallergic drugs and Bromopyrogallol Red (BPR) or Bromothymol Blue (BTB), which are more sensitive (ε = 1.03 -2.55 × 10 4 l mol -1 cm -1 ) than the official 10-12 (ε = 1.0 -2.1 × 10 3 l mol -1 cm -1) and the reported extractive 6 (ε = 5.43 × 10 3 l mol -1 cm -1 ) or direct 1-5 spectrophotometric methods (ε = 3.1 -9.61 × 10 3 l mol -1 cm -1 ) for the assay of the selected drugs, the structures of which are shown in Fig. 1. The proposed methods have been extended to the assay of these drugs in various pharmaceutical formulations. Experimental ApparatusAbsorbance measurements were made on a Hitachi UVvisible spectrophotometer U-2001 with 1 cm matched quartz cells. The pH measurements were made with a Schott Gerate pH meter CG 804. Elemental analysis was performed on a Thermoquest elemental analyzer EA 1110 CHN and a Nicolet FTIR spectrophotometer Impact 410 was used for recording the IR spectra of the complex. Reagents and samplesAll chemicals were of analytical or pharmaceutical grade and quartz-processed high-purity water was used throughout.Standard solutions of antiallergic drugs were prepared separately by dissolving 100 mg each of pure sample in distilled water and diluted up to the mark in a 100 ml volumetric flask. These solutions were stored in well-closed vessels, and direct contact with light was avoided. Standard solution was diluted as and when required. A 0.04% (w/v) of BPR and 0.05% (w/v) of BTB were prepared by dissolving first in a few drops of acetone and then diluted to the mark with distilled water in 100 ml calibrated flasks separately. Different buffers of various pH were prepared by following the standard methods. Determination of pure drugs Method using BPR.Aliquots of standard MDH or PMH solution were transferred into a series of 125 ml separating funnels. A 4 or 6 ml of BPR for MDH or PMH, 10 ml of chloroform and 5 ml of distilled water were added and mixed well....

Heteroassociation of the bromine-containing anions of sulfophthaleins in aqueous solution

“…17-20 One of the most promising fields of application of BDSP as analytical reagents is the quanti tative determination of the range of components in bio agents and pharmaceuticals: antiviral (indinavir), 21 anti microbial (enoxacin), 22 antibacterial (gatifloxacin, 23 sparfloxacin, 24 ofloxacin 25 ), antihistaminic (oxomem azine), 26, 27 and hypotensive (irbesartan, 28 nifedipine, 29 dilti azem 30 ) agents, antidepressants (tianeptine, 31 trazodone, 32 sertraline, fluoxetine, venlafaxine 33 ), antiulcer agents (raniti dine), 34 etc. 35, 36 It is noteworthy that the high precision and rapid methods described above are based on the for mation of heteroassociates (ionic pairs) between the com ponent to be determined and the anionic forms of BDSP. Very often heteroassociates are extracted into an organic phase (tricloromethane, 21,22,25,27,29,30,32 dichlorometh ane 26, 36 ).…”

Development and Validation of Stability-Indicating RP-UPLC Method for the Determination of Methdilazine in Bulk Drug and in Pharmaceutical Dosage Form

“…Quantification of MDH has been achieved by high-performance liquid chromatography (HPLC) [4][5][6], liquid chromatography [7], spectrofluorimetry [8], differential fluorimetry, and differential UV-spectrophotometry [9]. Some visible spectrophotometric methods are also reported for the assay of on pharmaceuticals [10][11][12][13][14][15][16][17][18][19][20][21][22].…”

Analysis of pharmaceutical preparations containing antihistamine drugs by micellar liquid chromatography

“…The determination of antihistamines in pharmaceutical preparations for its quality control has been performed using several analytical techniques, such as volumetric analysis [2,3], voltametria [4], atomic absorption [5], fluorimetry [6,7], spectrophotometry [8][9][10][11][12], gas chromatography [13] liquid chromatography [14][15][16][17], capillary electrophoresis [18] and micellar electrokinetic chromatography [19,20].…”